NCTI Service Technician Conventional Correct Answers.
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NCTI
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NCTI
Which of the following is the distance occupied by 1 hertz (Hz)? - Ans Wavelength.
What is the return signal pass band frequency used in most of North America? - Ans 5-42 MHz.
What is the primary difference between coaxial express cable and coaxial distribution cable in an HFC architectur...
which of the following is the distance occupied by 1 hertz hz ans wavelength what is the return signal pass band frequency used in most of north america ans 5 42 mhz what is the primar
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NCTI Service Technician Conventional
Correct Answers
Which of the following is the distance occupied by 1 hertz (Hz)? - Ans Wavelength.
What is the return signal pass band frequency used in most of North America? - Ans 5-
42 MHz.
What is the primary difference between coaxial express cable and coaxial distribution
cable in an HFC architecture? - Ans Taps are installed on coaxial distribution cable
and not on express cable.
Which testing device is the best to use to measure cable faults? - Ans A time domain
reflectometer (TDR).
Which of the following is used to define the waveform of an optical signal? - Ans
Wavelength.
What is the function of an interdiction unit? - Ans An interdiction unit controls the level
of service to the drop ports it contains.
Which of the following devices is an active device? - Ans An addressable tap
The impedance of coaxial cable or a device is made up of the combined effects of which
three electrical properties? - Ans Resistance, inductance, and capacitance.
When all other factors are equal, if the bonding wire and the cable connecting the drop
cable to consumer electronics are the same size, which should be shorter in order to
correctly bond the installation? - Ans The bonding wire.
What is the definition of tap value? - Ans The signal loss between the tap input port
and the tap ports.
Alternating current is a current - Ans That changes direction (or alternates) in the
conductor each time the potential difference applied to the ends of the conductor
changes (or alternates) its polarity.
A simple AC generator containing a wire loop rotating between the poles of a magnet
produces AC voltage - Ans Through magnetism and mechanical motion.
The amount of power lost as a result of conversion to heat in power transmission lines -
Ans Is directly proportional to the amount of resistance present and to the square of
the amount of current.
,To transmit AC power efficiently, what power line voltage-current combination would
deliver the same amount of power as 10 amps and 10,000 volts, but with the least heat
loss? - Ans 2 amps and 50,000 volts.
In a power transmission circuit, the transformer located near the user's home, typically -
Ans Converts the high voltage, low current combination carried on the transmission
lines to a low voltage, high current combination for residential use.
All true AC waveforms - Ans Always are symmetrical about the horizontal axis.
The output voltage waveform generated by an AC generator during one complete
rotation of the generator's armature - Ans Is called a sine wave.
The square wave and the sawtooth wave AC waveforms - Ans Seem to decrease
"instantly" from a maximum positive value to a maximum negative value of voltage or
current.
The polarity of a DC waveform - Ans Does not change.
A fluctuating DC waveform - Ans Can be identical to an AC waveform, except that the
fluctuating DC waveform never changes polarity.
One cycle - Ans Is equal to one complete rotation of the armature of an AC generator.
What is the wavelength of one cycle of an AC waveform when: (1) the frequency of the
waveform is 80 Hz; (2) the speed of light is 300,000 kilometers per second; and (3) the
waveform has an amplitude of 5 volts? - Ans 3,750 km.
What is the time period of one cycle or wavelength of an AC waveform when the
frequency of the waveform is 50 Hz? - Ans 0.0200 seconds.
A phase angle - Ans Is the amount of time, in degrees, it takes the waveform to
change from the zero-degree reference point to any other point on the waveform.
The amplitude of a waveform is defined as - Ans The maximum level of either half-
cycle of the waveform.
The peak value of a waveform - Ans Is another name for the amplitude of the
waveform.
What is the peak-to-peak value of an AC waveform when: (1) the frequency is 60 Hz;
(2) the maximum negative value of the waveform is -4 volts; and (3) the effective value
of the waveform is 2.83 volts? - Ans 8.0 volts peak-to-peak.
, Which of the following statements about instantaneous values is true? - Ans The
instantaneous value is the value of a single point on the AC waveform at a specific
moment, or instant, of time.
The average value - Ans Is 3.18 volts for a waveform with a peak value of 5 volts.
What is the average value of an AC waveform that has an effective value of 8 volts? -
Ans 7.2 volts.
How is an AC resistive circuit the same as a DC resistive circuit? - Ans They have
similar Ohm's law and power relationships, with certain exceptions.
Unless specified otherwise, I = E/R for an AC circuit is assumed to mean - Ans The
effective value of the current equals the effective value of the voltage divided by the
resistance.
The basic power relationship "p(t) = e(t)i(t)" - Ans Means the power at a specific instant
equals the voltage at that same instant times the current at that instant.
In resistive AC circuits, - Ans The AC power waveform has two positive half-cycles and
two positive peaks.
Eddy currents - Ans Can cause a loss of power in an AC circuit.
The eddy-current losses in the conductors of an AC circuit are - Ans Dependent on the
frequency of the current flowing through the conductors.
Skin-effect losses - Ans Are reduced by using multiple-strand conductors instead of a
single, large diameter conductor.
What is the value of the current when: (1) the effective voltage is 120 volts; (2) the
resistance of the source is 3 ohms; (3) the resistance of the conductors is 2 ohms; and
(4) the resistance of the load is 5 ohms? - Ans 12.00 amperes.
What is the power consumed by the load when: (1) the voltage across the load is 7.5
volts; (2) the current flowing through the circuit is 0.25 amperes; and (3) the resistance
of the load is 30 ohms? - Ans 1.88 watts.
What is the power consumed by coaxial cable loop resistance when: (1) the current of
the coaxial cable circuit is 5 amperes; (2) the loop resistance of the coaxial cable
is .9345 ohms; and (3) the AC power source has an effective voltage of 60 volts? - Ans
23.36 watts.
Induction - Ans Is the production of an electromotive force (emf) in a conductor by
changes in the magnetic field around the conductor.
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